The .489 lift will become .522, Still well within the range of your springs.
Should present no problem using 1.6 rockers.
JA

 

And John,

What would be the difference of havind .522 lift or .489?
The duration will still remain the same? Any advantages?

Thanks for your reply,
Houman

 

I think in theory the duration will be a little longer. When they quote duration it is usually at .050 and with the 1.5 rockers. With 1.6 rockers you will get to .050 faster and stay there longer to increase the duration. I dont think it will be more than 2 or 3 degrees but I didnt actually sit down with paper and figure it out. I think the reason they use .050 is because thats where air flow is starting to flow to any amount.

 

Houman, thats one great looking Camaro that you got in Iran. Seems that the American cars that are out of America are all mint

 

More lift per durations generally equals a bit more horsepower. You are giving more area for the air to flow in, in the same amount of time. More air/fuel translates into more power. Provided the rest of the system is matched and up to par.

If you have the money, do it. Its not a groundbreaking upgrade, but I did it, and was happy to have the extra lift.

 

timming of the events does not change. just lift.

 

Formula below:
valve lift divided by rocker ratio = lobe lift

.489 / 1.5= .326" lobe lift

lobe lift multiplied by rocker ratio = valve lift

.326 x 1.6 = .5216" valve lift


You will gain around 2-3 degrees in duration - AKA - the lazy mans cam

Be sure you have piston to valve clearence - this isn't a big change in lift so you should be fine.

 

when you get to base circle lift is 0. 0 x 1.6 is still 0. time doesnt change. right?

 

What is your point?

 

hey man , im just trying to acurately answer this mans question. im not being smart in the least.

 

I did'nt think you were being smart at all.

Just wanted to understant what you were saying.

 

on the degree wheel. you find the centerline and from ivo to ivc is controlled by the lobe on the cam. the rockers just a multiplier. the actual duration does not increase. just lift.

i would check for valve clearance homan.

 

You make a valid point!

I have read in a number of jurnals that you pick up 2 - 3 degrees in duration, but thinking about what you are saying makes absolute sense - Hmmmm!

 

on the degree wheel. you find the centerline and from ivo to ivc is controlled by the lobe on the cam. the rockers just a multiplier. the actual duration does not increase. just lift.

i would check for valve clearance homan.

Thanks Spinn,

Actually, I've got 345 NP's Flat Tops with 4 valve relives.
How do I have to check for valve clearance?

It seems like some professional stuff man? And After all, how much more horses am I gonna git out of this?

Any indication?

Thanks again for all your advises.

Houman

 

HP depends on your combo - your gains will be nominal, however, if you can fit them why not?

 

Houman, thats one great looking Camaro that you got in Iran. Seems that the American cars that are out of America are all mint

Thanks for the complements Charlie. Actually not all of them, we've also got lots of wreckes here.

But some very good Americans, such as a couple of GTO Judges, Z28's, Stingrays, Daytona Chargers, and also one camaro Motion.

I love my SS 350, he's been nice to me ever since I've got him and he never takes me to mechanic. I always take him.

 

HP depends on your combo - your gains will be nominal, however, if you can fit them why not?

TCAMARO,

Thanks for your comments, do you think that I can fit them?

And if the gains are not noticeable, why should I go on with so much doubt?
Don't you think that I'll be off better with the 1.5 ratio?
I'm really confused.

I need a strait advise on this.

 

Sorry for the confusion.

It is important to know how far your piston is in the hole, head gasket thickness and cylinder head cc's in order to properly determine clearance without removing the head.

If you or the engine builder does not know changinig the rockers will by no means give you seat of paint gains-therefore I would not do it. If you/someone knows the specifics to your build then go fot it! Otherwise it's not worth the trouble.

 

i use model clay hats and place them on the piston. rotate crank a least 2 revolutions. i think you can also use a light spring too, with a dail indicator, depress valve measure travel.

t camaro is right depends on your combo

miniumum varies. like .110" ? with alumminum rods/ steel like .090"

 

And if the gains are not noticeable, why should I go on with so much doubt?
Don't you think that I'll be off better with the 1.5 ratio?
I'm really confused.

You aren't likely to notice a 10 or 15 hp change but overtime it adds up. Whether you notice it or not, more power is there and your engine is using it. 1 10hp upgrade wont do a lot. But you throw a couple more on top of that over time and your power starts to add up. Like I said, if you can afford it, do it.

 

TCAMARO,

Thanks for your comments, do you think that I can fit them?

And if the gains are not noticeable, why should I go on with so much doubt?
Don't you think that I'll be off better with the 1.5 ratio?
I'm really confused.

I need a strait advise on this.

Advice? Here is some advice. Take your cam card to the cam grinder and ask the nice man if 1.6s will provide any increase in performance to your particular combination. In many cases it will. In some cases it wont and, in still other cases, it could even be a detriment. He is the only one that can answer this question on the basis of logical input.

Regardless of which rockers you choose, mock that stuff up and check piston to valve clearance, geometry, and get a degree wheel on er also.

These are the only steps needed to achieve no doubt nirvana.

 

The advertised duration will not change(or at least not any measurable amount). The duration @.050" will increase ever so slight, although enough to measure not a major player in this scenario. The major advantage is faster opening and closing of the valve and increased lift vs duration #'s, edging closer to a roller profile.

 

timming of the events does not change. just lift.

If you put a degree wheel on the motor and turn the engine until the cam lobe lifts .03333 and the put on a 1.5 rocker you will have .050 lift. If you remove the 1.5 rocker without moving the engine and put on a 1.6 rocker you would have .053328 lift. To get back to the .050 lift you would have to back the motor up until you had .03125 lobe lift. You would get the same effect on the other end of the cam lobe. So the .050 lift to .050 lift duration would increase. I hope this clarifies it a little.

 

Yes, duration measured at .050 does change. Overall duration (degrees of lift area) does not. That can only be changed via cam grind.

Edited because I am a dork.

 

Lift, yes. not duration at 50, lift at 50.

do you know what they mean by duration at .050? it just exaturates the lift. it cant change when it happens. right?

at .050" lifter rise